Neutral to earth voltage reduction methods in three-phase four wire distribution systems

Neutral to earth voltage can vary significantly depending on the load unbalance. Here, an analysis of neutral to earth voltage in multi-grounded three-phase four-wire distribution system is presented that considers load unbalance and the effect of explicitly represented neutral wire. A multiphase load flow algorithm is developed based on backward/forward sweep to examine the effects of various factors on the neutral to earth voltage (NEV), including unsymmetrical system configuration and load unbalance. The magnitude of NEV is investigated under various conditions on the number of grounding rods per feeder lengths and the grounding rods' resistance. The algorithm and the associated models are tested on IEEE 13 bus system.